This grant requests support to establish a Research Irradiation Facility in the Medical Center at the University of Alabama in Birmingham. This facility will allow UAB investigators to irradiate small animals, e.g., mice and rats, and single cell suspensions for a variety of uses in biomedical research. The current needs are met by a Picker-Vanguard X-ray machine which is over 20 years old, difficult to calibrate, in frequent need to repairs, and thus often unavailable to UAB researchers. The Cesium-137 units proposed in this grant will satisfy all of the irradiation requirements of UAB Medical Center investigators. Many studies with tumors and with lymphoid cells require the use of sublethal or lethal doses of irradiation in either mice or rats. Furthermore, the heavy load of tissue, blood cells, lymphoid and "feeder" cells for in vitro cultures has placed a heavy demand for a cell irradiation unit. The widespread production of both T and B cell hybridomas and T cell cloning methodology by several UAB investigators requires that daily feeder irradiation be performed. The proposed units are reliable and will satisfy these needs with a minimum cost to the investigator. This proposal is health related, and will provide UAB biomedical scientists with the capability to satisfy a variety of experimental needs and will facilitate a number of new studies which are not possible at the present time.